Irrigation system track assembly with adjustable tow

ABSTRACT

A track assembly for a mobile tower of an irrigation system includes a mounting bracket; a gearbox assembly and rotatable drive wheel hub attached to the mounting bracket; a drive wheel attached to the drive hub; a rotatable tension wheel hub attached to the mounting bracket and spaced from the drive hub; a tension wheel attached to the tension wheel hub; a track belt trained over the drive wheel and the tension wheel and driven by the drive wheel to propel the mobile tower; and structure for pivotally mounting the mounting bracket to the mobile tower.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to agricultural irrigation systems. Moreparticularly, the invention relates to an improved track assembly for anirrigation system.

2. Background

Agricultural irrigation systems such as central pivot irrigationmachines and lateral move irrigation machines are commonly used toirrigate crops. A central pivot irrigation machine typically includes,among other things, a central pivot communicating with a pressurizedwater supply and a series of spans formed from mobile support towersconnected to the central pivot and to one another by truss-typeframework sections. A water distribution conduit is supported by theframework sections and a number of sprinkler heads, spray guns, dropnozzles, or other fluid-emitting devices are spaced along the length ofthe conduit. A lateral move irrigation system is similar except it doesnot include a central pivot but instead has several aligned spans thatmove laterally across a rectangular-shaped field.

The mobile towers of central pivot and lateral move irrigation systemsare typically supported on wheel and tire assemblies that are driven bysuitable motors. These wheel and tire assemblies sometimes slip, getstuck, and/or create ruts, especially in wet low-lying areas or onhills.

To alleviate these problems, a mobile tower's tires can be replaced withtrack assemblies similar to those installed on earth-movers andtractors. Track assemblies provide better traction and have a muchlarger footprint and better ground “floatation” and therefore don'tcreate ruts and damage crops as much as tires do.

Unfortunately, known irrigation system track assemblies are complex andexpensive and are therefore not practical for many applications.Moreover, known track assemblies sometimes provide too much traction andare therefore difficult to guide in a circular or other non-straightpath without creating excessive stress on the irrigation system. Infact, applicant has discovered that known track assemblies can cause thespans of smaller irrigation systems to buckle while turning. Similarly,applicant has discovered that known track assemblies create excessoff-set loading on gearbox output shafts and other irrigation systemcomponents.

To allow an irrigation system to more easily follow a circular or othernon-linear path, its wheels or track assemblies can be provided with aselected steering angle or tow. Unfortunately it is difficult andtime-consuming to set the tow on existing irrigation system trackassemblies.

SUMMARY

The present invention solves the above described problems and providesan improved track assembly for irrigation systems that doesn't sufferfrom the above-described problems and/or other problems. Moreparticularly, the present invention provides a track assembly withbetter traction and flotation than wheel and tire assemblies, but thatdoes not create the buckling and off-set loading problems of existingirrigation system track assemblies. The track assembly of the presentinvention is also less complex and costly than known irrigation systemtrack assemblies and is therefore practical for use with nearly anyirrigation system. The tow or steering angle of the track assembly canalso be more quickly and easily set and adjusted.

An embodiment of the track assembly is configured for replacing at leastone wheel on an irrigation system mobile tower and broadly comprises amounting bracket; a gearbox assembly and rotatable drive wheel hubattached to the mounting bracket; a drive wheel attached to the drivehub; a rotatable tension wheel hub attached to the mounting bracket andspaced from the drive hub; a tension wheel attached to the tension wheelhub; and a track belt trained over the drive wheel and the tension wheeland driven by the drive wheel to propel the mobile tower.

In accordance with one important aspect of the invention, the trackassembly also includes structure for pivotally mounting the mountingbracket to the mobile tower to permit the drive hub and attached drivewheel to turn slightly to more easily follow a curved path. In oneembodiment, the structure includes a hinge plate attached to the mobiletower and a locking pin for pivotally coupling the mounting bracket tothe hinge plate. The structure may also include an eyelet or turnbuckleto adjust the pivot angle of the mounting bracket relative to the hingeplate to achieve a preselected steering angle or tow.

The track assembly may further include structure for adjusting amounting angle of the gearbox on the mounting bracket to further adjustthe steering angle or tow of the track assembly. In one embodiment, thestructure includes a shim or similar device for placement between thetrack assembly's gearbox and mounting bracket. This allows the tow orsteering angle of each track assembly to be selectively adjusted toaccommodate its particular mobile tower. For example, the tow of all thetrack assemblies of an irrigation system may be set during initialsystem set-up and installation. The tow of some of the track assembliesmay then be modified in the field with the hinge plate, mountingbracket, and turnbuckle described above. Then, the tow of selected onesof the track assembly's may be adjusted even further with one or more ofthe shims.

This summary is provided to introduce a selection of concepts in asimplified form that are further described in the detailed descriptionbelow. This summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used to limit the scope of the claimed subject matter. Other aspectsand advantages of the present invention will be apparent from thefollowing detailed description of the embodiments and the accompanyingdrawing figures. For example, the principles of the present inventionare not limited to central pivot irrigation systems, but may beimplemented in other types of irrigation systems including linear moveirrigation systems.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

Embodiments of the present invention are described in detail below withreference to the attached drawing figures, wherein:

FIG. 1 is a perspective view of an exemplary central pivot irrigationsystem on which the track assembly of the present invention may beimplemented.

FIG. 2 is a perspective view of one of the mobile towers of theirrigation system shown with two track assemblies installed thereon.

FIG. 3 is an enlarged perspective view in partial section of one of thetrack assemblies shown mounted to a drive tube of a mobile tower.

FIG. 4 is an exploded perspective view of one of the mobile towers andone of its track assemblies.

FIG. 5 is a top view in partial section of one of the mobile towers andits two track assemblies with the mobile tower shown in dashed lines.

FIG. 6 is an enlarged top view in partial section of one of the trackassemblies shown in FIG. 6.

The drawing figures do not limit the present invention to the specificembodiments disclosed and described herein. The drawings are notnecessarily to scale, emphasis instead being placed upon clearlyillustrating the principles of the invention.

DETAILED DESCRIPTION

The following detailed description of embodiments of the inventionreferences the accompanying drawings. The embodiments are intended todescribe aspects of the invention in sufficient detail to enable thoseskilled in the art to practice the invention. Other embodiments can beutilized and changes can be made without departing from the scope of theclaims. The following detailed description is, therefore, not to betaken in a limiting sense. The scope of the present invention is definedonly by the appended claims, along with the full scope of equivalents towhich such claims are entitled.

In this description, references to “one embodiment”, “an embodiment”, or“embodiments” mean that the feature or features being referred to areincluded in at least one embodiment of the technology. Separatereferences to “one embodiment”, “an embodiment”, or “embodiments” inthis description do not necessarily refer to the same embodiment and arealso not mutually exclusive unless so stated and/or except as will bereadily apparent to those skilled in the art from the description. Forexample, a feature, structure, act, etc. described in one embodiment mayalso be included in other embodiments, but is not necessarily included.Thus, the present technology can include a variety of combinationsand/or integrations of the embodiments described herein.

Turning now to the drawing figures, and initially FIG. 1, an exemplaryirrigation system 10 on which principles of the present invention may beimplemented is illustrated. The illustrated irrigation system 10 is acentral pivot irrigation system that broadly comprises a fixed centralpivot 12 and a main section 14 pivotally connected to the central pivot.The irrigation system 10 may also comprise an extension arm (alsocommonly referred to as a “swing arm” or “corner arm”) pivotallyconnected to the free end of the main section.

The fixed central pivot 12 may be a tower or any other support structureabout which the main section 14 may pivot. The central pivot has accessto a well, water tank, or other source of water and may also be coupledwith a tank or other source of agricultural products to injectfertilizers, pesticides and/or other chemicals into the water forapplication during irrigation.

The main section 14 may comprise a number of mobile support towers16A-D, the outermost 16D of which is referred to herein as an “endtower”. The support towers are connected to the fixed central pivot 12and to one another by truss sections 18A-D or other supports to form anumber of interconnected spans. The irrigation system 10 illustrated inFIG. 1 has four mobile support towers 16A-D; however, it may compriseany number of mobile support towers without departing from the scope ofthe present invention.

Each mobile tower may include a drive tube 20A-D on which a pair oftrack assemblies 22A-D is mounted. Embodiments of the track assemblies22A-D are described in more detail below. A drive motor 24A-D and driveshaft 26A-D are mounted to the drive tube for driving at least one ofthe track assemblies. The motors 24A-D may include integral or externalrelays so they may be turned on, off, and reversed. The motors may alsohave several speeds or be equipped with variable speed drives. Insteadof track assemblies, some of the mobile towers 16A-D may have wheelsdriven by drive motors.

As is well known, the drive motors are controlled by a suitable safetysystem such that they may be slowed or completely shut down in the eventof the detection of an adverse circumstance, all of which is disclosed,for example, in U.S. Pat. No. 6,042,031 to Christensen, et al.incorporated herein by reference in its entirety.

Each of the truss sections 18A-D carries or otherwise supports a conduitsection 28A-D or other fluid distribution mechanism that is connected influid communication with all other conduit sections. A plurality ofsprinkler heads, spray guns, drop nozzles, or other fluid-emittingdevices are spaced along the conduit sections 28A-D to apply waterand/or other fluids to land underneath the irrigation system.

The irrigation system 10 may also include an optional extension arm (notshown) pivotally connected to the end tower 16D and supported by a swingtower with steerable wheels driven by a motor. The extension arm may bejoined to the end tower by an articulating pivot joint. The extensionarm is folded in relative to the end tower when it is not irrigating acorner of a field and may be pivoted outwardly away from the end towerwhile irrigating the corners of a field.

The irrigation system 10 may also include one or more high pressuresprayers or end guns 30 mounted to the end tower 16D or to the end ofthe extension arm. The end guns are activated at the corners of a fieldor other designated areas to increase the amount of land that can beirrigated.

The irrigation system 10 may also include a main control system forcontrolling movement of the mobile towers 16A-D and operation of thefluid-emitting devices in accordance with an irrigation design program.The main control system may include a processor or other computingdevice with inputs that receive positional information from one or moreGPS receivers mounted to the end tower or elsewhere. The processor mayalternatively receive position information from angle encoders mountedbetween the central pivot and a first span of the main section. Theprocessor may also include outputs connected to relay-controlled valvesconnected to the water-emitting devices and relay-controlled electricmotors connected to the drive wheels of the mobile towers.

Turning now to FIGS. 2-4, embodiments of the track assemblies 22A-D willnow be described in more detail. As shown, a mobile tower 16D mayinclude a pair of track assemblies, each of which broadly comprises amounting assembly 32; a gearbox assembly 34 and rotatable drive wheelhub 36; a drive wheel 38; a rotatable tension wheel hub 40; a tensionwheel 42; and a track belt 44. All of the track assemblies 22A-D areessentially identical; therefore only one track assembly 22D will bedescribed in detail in this application.

As best shown in FIGS. 3 and 4, the mounting assembly 32 is attached toone end of the drive tube 20D and is provided for supporting the othercomponents of the track assembly to the mobile tower. An embodiment ofthe mounting assembly 32 includes a hinge plate 46 connected to thedrive tube and a mounting bracket 48 pivotally connected to the hingeplate by a locking pin 56. The hinge plate 46, mounting bracket 48, andlocking pin 56 together provide structure for pivotally mounting themounting bracket 48 to the mobile tower to permit the drive hub 36,drive wheel 38 to turn slightly with a desired steering angle or tow.

The hinge plate 46 includes a vertically extending plate 50 welded orotherwise fastened to one end of the drive tube 20D and a pair ofspaced-apart, horizontally extending flanges 52 extending from thevertical plate. Vertically aligned pin holes 54 extend through theflanges for receiving a locking pin 56 as described below. The hingeplate 46 also includes a rearwardly extending horizontal leg 58 that ispositioned below the drive tube. A bolt hole may be positioned in theleg and aligned with a bolt hole on the mounting bracket as describedbelow.

The mounting bracket 48 includes a vertically-extending plate 60 and apair of spaced-apart horizontally-extending flanges 62 extending fromthe vertical plate. Vertically aligned pin holes 64 extend through theflanges. The mounting bracket 48 may be attached to the hinge plate 46by placing the mounting bracket flanges 62 over the hinge plate flanges52 so as to align the holes 54 and 64, and then placing the locking pin56 through the holes 54 and 64. This arrangement permits the mountingbracket 48 to pivot relative to the hinge plate 46 and the drive tube20D so the track assembly 22D may turn slightly to follow a curved path.A threaded eyelet or turnbuckle may attach the mounting bracket to thedrive tube or to the hinge plate. The pivot angle of the mountingbracket may then be selected by adjusting the eyelet or turnbuckle toachieve a pre-selected turning radius or tow. Alternatively, a bolt maybe positioned through a hole 66 in the mounting bracket flange and intoa slot in the hinge plate leg to adjust the pivot angle of the bracketand the tow of the track assembly.

The track assembly 22D may further include structure for adjusting amounting angle of the gearbox 34 on the mounting bracket 48 to furtheradjust the turning radius or tow of the track assembly. In oneembodiment, the structure includes a shim 67 or similar device forplacement between the track assembly's gearbox 34 and mounting bracket48 to adjust the drive wheel's tow or turning angle. This allows the towof each track assembly to be selectively adjusted to accommodate itsparticular mobile tower. For example, the tow of all the trackassemblies may be set with each track assembly's the hinge plate,mounting bracket, and turnbuckle described above. Then, the tow ofselected ones of the track assemblies may be further adjusted with oneor more of the shims 67 as shown in FIGS. 5 and 6.

An embodiment of the shim 67 is best shown in FIG. 4 and includes agenerally planar main portion 69 and an angled leg 71. The main portion69 includes a pair of slots 73 or holes for accommodating bolts or otherfasteners that attach the gearbox assembly 34 to the mounting bracket48. The leg 71 extends from the main portion 69 at an angle to space oneend of the gearbox assembly 34 away from the mounting bracket 48. Thelength and/or angle of the leg 71 determines the angle of the gearboxassembly 34 relative to the mounting bracket 48 and thus the degree oftow of the track assembly. In one embodiment, the main portion of theshim is 8″ long and 4″ wide and the leg is 3″ wide and extends from themain portion at an angle of 5° to provide the track assembly withapproximately 3° of tow beyond that provided by the angular orientationof the mounting bracket on the hinge plate.

The mounting bracket 48 further includes a pair of spaced-apart,horizontally extending guide walls 68 that define an adjustment channeltherebetween. A pair of slots 70 are formed in the vertical plate 60between the guide walls, the purpose of which are described below.

The gearbox assembly 34 and drive wheel hub 36 are conventional and areattached to the mounting bracket 48 by bolts, screws, or other fastenersthat extend through holes in the vertical plate of the bracket. Thegearbox assembly 34 is then coupled to the drive shaft 20D of the motor24D in a conventional manner.

The drive wheel 38 is attached to the drive wheel hub 36 by threaded lugnuts or other fasteners. In one embodiment, the drive wheel 38 isapproximately 40″ in diameter and 10″ wide. A drive wheel of this sizeallows the track assembly to more closely match the wheel speed of atire that has been replaced with the track assembly so that the gearbox34 is not required to provide a significant RPM reduction for the trackassembly as is required with prior art track assemblies.

The tension wheel hub 40 is rotatably mounted to a support tube 72 whichis in turn positioned within the adjustment channel of the mountingbracket. The support tube 72 and tension wheel hub 40 may be shiftedwithin the length of the adjustment channel to adjust the distancebetween the drive wheel 38 and the tension wheel 42 and fixed in placeby a pair of bolts or other fasteners that extend through bolt holes inthe support tube and the slots 70 between the guide walls in themounting bracket.

The tension wheel 42 is attached to the tension wheel hub 40 by lug nutsor other fasteners. The tension wheel 42 guides, tensions, and supportsthe track belt 44. Importantly, no undercarriage is required. In oneembodiment, the tension wheel 42 is approximately 24″ in diameter and10″ wide.

The track belt 44 is trained over the drive wheel 38 and the tensionwheel 42 and driven by the drive wheel. The track belt 44 may be made ofrubber or any other suitable material and may include any tread pattern.An embodiment of the track belt is 175″ long and 12″ wide. The narrowerwidth of the track belt, drive wheel, and tension wheel and the reducedlength of the track belt, when compared to existing track assemblies forirrigation systems, reduces the footprint of the track assembly so itcan be used with smaller irrigation systems without causing spanbuckling. Moreover, the reduced width creates less off-set loading onthe gearbox output shaft.

To keep the track belt 44 centered on the drive wheel and the tensionwheel, the drive wheel 38 and the tension wheel 42 each include a numberof spaced-apart outwardly projecting pegs 74 and the track belt includesa number of spaced-apart holes 76 that receive the pegs.

Once the track assembly 22D is mounted to the mobile tower 16D asdescribed above, the tension in the track belt 44 can be adjusted byloosening the bolts holding the support tube 72 within the adjustmentchannel of the mounting bracket 48. The tension wheel hub 42 may then bemoved closer to the drive wheel hub 38 to reduce the tension on thetrack belt 44 or further from the drive wheel hub to increase thetension. In one embodiment, the tension wheel hub 42 and support tube 72may be moved by placing a conventional tire jack between the drive wheel38 and tension wheel 44 and adjusting it to achieve the desired tensionon the track belt.

As should be apparent from the above description, the present inventionprovides an improved track assembly for irrigation systems that doesn'tsuffer from the problems of prior art irrigation system trackassemblies. For example, the track assembly has better traction andflotation than wheel and tire assemblies but does not create thebuckling and off-set loading problems of prior art irrigation systemtrack assemblies. The track assembly of the present invention is alsoless complex and costly than known irrigation system track assembliesand is therefore practical for use with nearly any irrigation system.

The tow or steering angle of the track assembly may also be more easilyadjusted to accommodate a non-linear path of travel for the irrigationsystem.

Although the invention has been described with reference to theembodiments illustrated in the attached drawing figures, it is notedthat equivalents may be employed and substitutions made herein withoutdeparting from the scope of the invention as recited in the claims. Forexample, the principles of the present invention are not limited to theillustrated central pivot irrigation systems but may be implemented inany type of irrigation system including linear move irrigation systems.

1. A track assembly for a mobile tower of an irrigation system, thetrack assembly comprising: a mounting bracket; a gearbox assembly androtatable drive wheel hub attached to the mounting bracket; a drivewheel attached to the drive hub; a rotatable tension wheel hub attachedto the mounting bracket and spaced from the drive hub; a tension wheelattached to the tension wheel hub; a track belt trained over the drivewheel and the tension wheel and driven by the drive wheel to propel themobile tower; and structure for pivotally mounting the mounting bracketto the mobile tower.
 2. The track assembly as set forth in claim 1,wherein the structure for pivotally mounting the mounting bracketincludes a hinge plate for mounting to a drive tube of the mobile towerand a locking pin for pivotally supporting the mounting bracket to thehinge plate.
 3. The track assembly as set forth in claim 2, furthercomprising structure for adjusting a pivot angle of the mounting bracketwith respect to the mobile tower to adjust a steering angle or tow ofthe track assembly.
 4. The track assembly as set forth in claim 3,wherein the structure for adjusting the pivot angle of the mountingbracket comprises an eye bolt, turnbuckle, or other adjustable fastenercoupled between the mounting bracket and the mobile tower.
 5. The trackassembly as set forth in claim 1, further comprising structure foradjusting a mounting angle of the gearbox on the mounting bracket tofurther adjust the steering angle or tow of the track assembly.
 6. Thetrack assembly as set forth in claim 5, wherein the structure foradjusting the mounting angle of the gearbox includes a shim forplacement between the gearbox and the mounting bracket.
 7. The trackassembly as set forth in claim 1, wherein the drive wheel and thetension wheel each include a number of spaced-apart outwardly projectingpegs and the track belt includes a number of spaced-apart holes thatreceive the pegs to keep the track centered on the drive wheel and thetension wheel.
 8. The track assembly as set forth in claim 1, whereinthe drive wheel, the tension wheel, and the track belt are all less than13″ wide.
 9. The track assembly as set forth in claim 1, wherein thetrack belt is tensioned by the tension wheel alone without anundercarriage.
 10. A track assembly for a mobile tower of an irrigationsystem, the mobile tower having a drive tube, the track assemblycomprising: a hinge plate for attachment to one end of the drive tube; amounting bracket pivotally attached to the hinge plate; a gearboxassembly and rotatable drive wheel hub attached to the mounting bracket;a drive wheel attached to the drive wheel hub; a rotatable tension hubattached to the mounting bracket and spaced from the drive hub, thetension wheel hub being shiftable relative to the mounting bracket andthe drive wheel hub; a tension wheel attached to the tension wheel hub;a track belt trained over the drive wheel and the tension wheel anddriven by the drive wheel to propel the mobile tower; structure foradjusting a pivot angle of the mounting bracket with respect to themobile tower to achieve a desired turning radius or tow for the trackassembly; and structure for adjusting a mounting angle of the gearbox onthe mounting bracket to further adjust the turning radius or tow of thetrack assembly.
 11. The track assembly as set forth in claim 10, whereinthe structure for adjusting the pivot angle of the mounting bracketcomprises an eye bolt, turnbuckle, or other adjustable fastener coupledbetween the mounting bracket and the mobile tower.
 12. The trackassembly as set forth in claim 10, wherein the structure for adjustingthe mounting angle of the gearbox includes a shim for placement betweenthe gearbox and the mounting bracket.
 13. The track assembly as setforth in claim 10, wherein the mounting bracket includes a pair ofspaced-apart guide walls that define an adjustment channel, wherein thetension wheel hub is mounted to a support tube that can be moved along alength of the channel to tension the track belt.
 14. The track assemblyas set forth in claim 10, wherein the hinge plate includes a pair ofspaced-apart flanges with vertically aligned holes, wherein the mountingbracket includes a pair of spaced-apart flanges with vertically-alignedholes, and wherein the mounting bracket is pivotally attached to thehinge plate with a locking pin that fits through the aligned holes. 15.The track assembly as set forth in claim 10, wherein the drive wheel andthe tension wheel each include a number of spaced-apart outwardlyprojecting pegs and the track includes a number of spaced-apart holesthat are engaged by the pegs to keep the track centered on the drivewheel and the tension wheel.
 16. An irrigation system comprising: acentral pivot; a series of mobile towers connected to the central pivotand to one another by support structure, each mobile tower having adrive tube, a drive motor, and a drive shaft driven by the drive motor;and at least one track assembly for supporting at least one of themobile towers above a ground to be irrigated by the irrigation system,the track assembly comprising: a hinge plate for attachment to one endof the drive tube; a mounting bracket pivotally attached to the hingeplate; a gearbox assembly and rotatable drive wheel hub attached to themounting bracket; a drive wheel attached to the drive wheel hub; arotatable tension hub attached to the mounting bracket and spaced fromthe drive hub, the tension wheel hub being shiftable relative to themounting bracket and the drive wheel hub; a tension wheel attached tothe tension wheel hub; a track belt trained over the drive wheel and thetension wheel and driven by the drive wheel to propel the mobile tower;structure for adjusting a pivot angle of the mounting bracket withrespect to the mobile tower to achieve a desired turning radius or towfor the track assembly; and structure for adjusting a mounting angle ofthe gearbox on the mounting bracket to further adjust the turning radiusor tow of the track assembly.
 17. The track assembly as set forth inclaim 16, wherein the structure for adjusting the pivot angle of themounting bracket comprises an eye bolt, turnbuckle, or other adjustablefastener coupled between the mounting bracket and the mobile tower. 18.The track assembly as set forth in claim 16, wherein the structure foradjusting the pivot angle of the mounting bracket comprises an eye bolt,turnbuckle, or other adjustable fastener coupled between the mountingbracket and the mobile tower.
 19. The irrigation system as set forth inclaim 16, wherein the mounting bracket includes a pair of spaced-apartguide walls that define an adjustment channel, wherein the tension wheelhub is mounted to a support tube that can be moved along a length of thechannel to tension the track belt.
 20. The irrigation system as setforth in claim 16, wherein the drive wheel, the tension wheel, and thetrack belt are all less than 13″ wide.